Antsy Acacias

Madeleine Ball — Tue, 22 Jan 2008 18:55:00 +0000

While reading up on giraffes and acacias on the internet, I noticed that the acacia featured in the original Science article wasn't in Wikipedia at all - not even a stub! The acacia, Acacia drepanolobium (Whistling Thorn) has a ton of info about it lying around on the internet, so it definitely deserves a wikipedia entry.

I found a creative commons photo on Flickr and the photographer, Martin Sharman, graciously changed the licensing on the photo to allow for commercial usage so I could use it in the wikipedia article. So I made the article, and I think the subject is pretty cool - this tree has a neat symbiosis with several species of ants, check it out.

Berry Butt Ants

Madeleine Ball — Thu, 17 Jan 2008 20:24:00 +0000

The first known example of parasite induced fruit mimicry: Scientists report (in the April issue of American Naturalist) the discovery of a parasitic worm that infects ants and turns their butts bright red -- so they resemble berries. The parasite also changes their behavior, causing them to wave their butt around in the air. A bird spies the "berry", eats it up and is infected. Bird poop is fed upon by the ants, completing the parasitic cycle.

Bug Biomimicry - Eyes, Ears, and Minds

Madeleine Ball — Mon, 08 May 2006 02:16:00 +0100

Sometimes mother nature inspires engineering. Sometimes especially hard problems are solved by organisms in ways we might not have imagined on our own. Bugs seem like unlikely muses, but they've inspired many an engineer.

Recently Science Magazine posted a news item about a synthetic lens that behaves much like an insect eye. The problem was this - how to create a very small camera that captures a wide angle light? A fisheye lens would be the obvious solution, but those are hard to create on a small scale.

Drawing inspiration from insect eyes, Jeoung, Kim, & Lee have created artificial compound eyes:

Now, I'm not clear on how detectors are set up to receive light that's captured by the polymer, but the pictures sure look cool.

Multi-directional vision isn't the only the only thing we have trouble miniaturizing - sound localization has also been difficult to miniaturize.

Humans seem to use the difference between the ears in volume of sound and time it takes to arrive to localize sounds. This was first described by Lord Rayleigh as the "duplex theory of localization".

But this system can't work for flies. With the speed of sound at 350 meters per second, a half a centimeter seperation of ears - huge in the world of bugs - only nets a 15 microsecond difference. Humans, with 20 centimeters of seperation between the ears, enjoy 600 microseconds. Now, human reaction time is at best around 300,000 microseconds; it's amazing that 600 microseconds is enough to be preserved by carefully timed propagation through axons, but 15 microseconds is simply lost to neuronal noise.

But bugs can find noises! Ormia is a parasitic fly that likes to lay its eggs on grasshoppers, and it has ears that are a scant half millimeter apart. And yet they can localize sound as well as humans. They need to, to find the chirping male grasshoppers that will host as food and home to their parasitic children.

They accomplish this trick through linking the ears' oscilliatory motions. This results in vibration differences - in both level and timing - between the two ears, caused by small differences in the timing of the sound's arrival.

This clever solution has inspired engineers to create Ormia-based miniature directional microphones.

Finally, bug brains. Now, it's true that bug brains aren't very big, but bugs have interesting swarm properties. And when it comes to making robots, the simplest behaviors of living things are the most realistic thing we could try to imitate. No one falls for a talking pseudo-human robot, but a robotic bug really looks alive!

I heard about BEAM robots (Biology Electronics Aesthetics Mechanics, or something like that) from an article on Make magazine's blog. While BEAM philosophy isn't necessarily about bugs, that's what these things look like.

The bugbots at the Maker Faire were solar-powered. Sunlight doesn't give enough energy to continuously drive a motor, but capacitors can collect the energy to a critical point and release to create bursts of action. The bugs hop around in the sunlight, some of them attracted to it - moving towards their food source!

I really want to build one of these solar bugs. They sell kits at www.solarbotics.com and a lot of community (advice, guides, designs) exists at the solarbotics-hosted community at www.solarbotics.net.

Mad Prime: Tag insects

Antsy Acacias

Berry Butt Ants

Bug Biomimicry - Eyes, Ears, and Minds